scholarly journals Exportin-1-Dependent Nuclear Export of DEAD-box Helicase DDX3X is Central to its Role in Antiviral Immunity

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1181 ◽  
Author(s):  
Steven M. Heaton ◽  
Sarah C. Atkinson ◽  
Melissa N. Sweeney ◽  
Sundy N. Y. Yang ◽  
David A. Jans ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Virus Production ◽  
Transcriptome Profiling ◽  
Antiviral Immunity ◽  
Guanine Nucleotide Binding Protein ◽  
Immune Genes ◽  
Dead Box ◽  
Nucleocytoplasmic Distribution ◽  
Hiv 1

DEAD-box helicase 3, X-linked (DDX3X) regulates the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR)-mediated antiviral response, but can also be a host factor contributing to the replication of viruses of significance to human health, such as human immunodeficiency virus type 1 (HIV-1). These roles are mediated in part through its ability to actively shuttle between the nucleus and the cytoplasm to modulate gene expression, although the trafficking mechanisms, and impact thereof on immune signaling and viral infection, are incompletely defined. We confirm that DDX3X nuclear export is mediated by the nuclear transporter exportin-1/CRM1, dependent on an N-terminal, leucine-rich nuclear export signal (NES) and the monomeric guanine nucleotide binding protein Ran in activated GTP-bound form. Transcriptome profiling and ELISA show that exportin-1-dependent export of DDX3X to the cytoplasm strongly impacts IFN-β production and the upregulation of immune genes in response to infection. That this is key to DDX3X’s antiviral role was indicated by enhanced infection by human parainfluenza virus-3 (hPIV-3)/elevated virus production when the DDX3X NES was inactivated. Our results highlight a link between nucleocytoplasmic distribution of DDX3X and its role in antiviral immunity, with strong relevance to hPIV-3, as well as other viruses such as HIV-1.

scholarly journals RanGTP-Regulated Interactions of CRM1 with Nucleoporins and a Shuttling DEAD-Box Helicase

1999 ◽  
Vol 19 (9) ◽  
pp. 6276-6285 ◽  
Author(s):  
Peter Askjaer ◽  
Angela Bachi ◽  
Matthias Wilm ◽  
F. Ralf Bischoff ◽  
Daniel L. Weeks ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Binding Assay ◽  
Specific Binding ◽  
Nuclear Export Signal ◽  
Trimeric Complex ◽  
Dead Box ◽  
Egg Extract ◽  
Nucleocytoplasmic Distribution ◽  
Export Signal ◽  
Selection Of

ABSTRACT CRM1 is an export receptor mediating rapid nuclear exit of proteins and RNAs to the cytoplasm. CRM1 export cargoes include proteins with a leucine-rich nuclear export signal (NES) that bind directly to CRM1 in a trimeric complex with RanGTP. Using a quantitative CRM1-NES cargo binding assay, significant differences in affinity for CRM1 among natural NESs are demonstrated, suggesting that the steady-state nucleocytoplasmic distribution of shuttling proteins could be determined by the relative strengths of their NESs. We also show that a trimeric CRM1-NES-RanGTP complex is disassembled by RanBP1 in the presence of RanGAP, even though RanBP1 itself contains a leucine-rich NES. Selection of CRM1-binding proteins from Xenopus egg extract leads to the identification of an NES-containing DEAD-box helicase, An3, that continuously shuttles between the nucleus and the cytoplasm. In addition, we identify the Xenopus homologue of the nucleoporin CAN/Nup214 as a RanGTP- and NES cargo-specific binding site for CRM1, suggesting that this nucleoporin plays a role in export complex disassembly and/or CRM1 recycling.

scholarly journals A New Nucleoporin-like Protein Interacts with Both HIV-1 Rev Nuclear Export Signal and CRM-1

1999 ◽  
Vol 274 (24) ◽  
pp. 17309-17317 ◽  
Author(s):  
Géraldine Farjot ◽  
Alain Sergeant ◽  
Ivan Mikaélian
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Export Signal ◽  
Hiv 1

scholarly journals C19ORF66 is an Interferon-Stimulated Gene (ISG) which Inhibits Human Immunodeficiency Virus-1

2016 ◽  
Author(s):  
Weidong Xiong ◽  
Deisy Contreras ◽  
Joseph Ignatius Irudayam ◽  
Ayub Ali ◽  
Otto O. Yang ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Nuclear Export ◽  
Splice Variants ◽  
Nuclear Export Signal ◽  
Full Length ◽  
Type I ◽  
Immune Factor ◽  
Immunodeficiency Virus ◽  
P24 Protein ◽  
Hiv 1

ABSTRACTInnate immunity is the first line of defense against invading microbes1. The type I interferon (IFN) pathway plays a key role in controlling Human Immunodeficiency Virus type 1 (HIV-1) replication2,3. We identified an IFN-α stimulated gene C19ORF66 that we term Suppressor of Viral Activity (SVA). Full length SVA-1 protein inhibits HIV-1 by blocking virion production. SVA splice variants truncated at the C-terminus and/or disrupted at the nuclear export signal (NES) lose antiviral activity and localize to nucleus, while full length SVA-1 co-localizes with HIV-1 p24 protein in the cytoplasmic compartment of infected cells. SVA-1 is structurally and functionally conserved across species, including mouse and chimpanzee. We provide the first description of the effector function of the gene SVA/C190RF66 as an innate immune factor with anti-HIV-1 activity.

Location of the HIV-1 Rev protein during mitosis: inactivation of the nuclear export signal alters the pathway for postmitotic reentry into nucleoli

1996 ◽  
Vol 109 (9) ◽  
pp. 2239-2251 ◽  
Author(s):  
M. Dundr ◽  
G.H. Leno ◽  
N. Lewis ◽  
D. Rekosh ◽  
M.L. Hammarskjoid ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Nucleolar Protein ◽  
Early Prophase ◽  
Nucleolar Proteins ◽  
Late Telophase ◽  
Export Signal ◽  
Hiv 1 ◽  
Rev Protein

The HIV-1 Rev protein localizes predominantly to the nucleolus of HIV-1-infected or Rev-expressing cells. The subcellular location of Rev during mitotic nucleolar disintegration was examined at various stages of mitosis in synchronized Rev-expressing CMT3 cells. During early prophase Rev was predominantly located in disintegrating nucleoli and began to accumulate at the peripheral regions of chromosomes in late prophase, eventually distributing uniformly on all chromosomes in prometaphase. In anaphase Rev remained associated with the perichromosomal regions, but significant amounts of Rev were also seen in numerous nucleolus-derived foci. The movement of Rev from disintegrating nucleoli to perichromosomal regions and foci was similar to that of nonribosomal nucleolar proteins, including fibrillarin, nucleolin, protein B23 and p52 of the granular component. During telophase Rev remained associated with perichromosomal regions and mitotic foci until the nuclear envelope started to reform. When nuclear envelope formation was complete in late telophase, nonribosomal nucleolar proteins were present in prenucleolar bodies (PNBs) which were eventually incorporated into nucleoli; at the same time, Rev was excluded from nuclei. In contrast, a trans-dominant negative Rev protein containing an inactive nuclear export signal reentered nuclei by the nonribosomal nucleolar protein pathway in late telophase, associating with PNBs and reformed nucleoli. Rev protein reentry into postmitotic nuclei was delayed until early G1 phase, but before the arrival of ribosomal protein S6. Thus, Rev behaves like a nonribosomal nucleolar protein through mitosis until early telophase; however, its nuclear reentry seems to require reestablishment of both a nuclear import system and active nucleoli.

scholarly journals Nuclear Export Signal Masking Regulates HIV-1 Rev Trafficking and Viral RNA Nuclear Export

2016 ◽  
Vol 91 (3) ◽  
Author(s):  
Ryan T. Behrens ◽  
Mounavya Aligeti ◽  
Ginger M. Pocock ◽  
Christina A. Higgins ◽  
Nathan M. Sherer
Keyword(s):  
Gene Expression ◽  
Nuclear Export ◽  
Rna Binding ◽  
Nuclear Export Signal ◽  
Viral Gene Expression ◽  
Viral Gene ◽  
Virion Production ◽  
Export Signal ◽  
Hiv 1 ◽  
Rev Protein

ABSTRACT HIV-1's Rev protein forms a homo-oligomeric adaptor complex linking viral RNAs to the cellular CRM1/Ran-GTP nuclear export machinery through the activity of Rev's prototypical leucine-rich nuclear export signal (NES). In this study, we used a functional fluorescently tagged Rev fusion protein as a platform to study the effects of modulating Rev NES identity, number, position, or strength on Rev subcellular trafficking, viral RNA nuclear export, and infectious virion production. We found that Rev activity was remarkably tolerant of diverse NES sequences, including supraphysiological NES (SNES) peptides that otherwise arrest CRM1 transport complexes at nuclear pores. Rev's ability to tolerate a SNES was both position and multimerization dependent, an observation consistent with a model wherein Rev self-association acts to transiently mask the NES peptide(s), thereby biasing Rev's trafficking into the nucleus. Combined imaging and functional assays also indicated that NES masking underpins Rev's well-known tendency to accumulate at the nucleolus, as well as Rev's capacity to activate optimal levels of late viral gene expression. We propose that Rev multimerization and NES masking regulates Rev's trafficking to and retention within the nucleus even prior to RNA binding. IMPORTANCE HIV-1 infects more than 34 million people worldwide causing >1 million deaths per year. Infectious virion production is activated by the essential viral Rev protein that mediates nuclear export of intron-bearing late-stage viral mRNAs. Rev's shuttling into and out of the nucleus is regulated by the antagonistic activities of both a peptide-encoded N-terminal nuclear localization signal and C-terminal nuclear export signal (NES). How Rev and related viral proteins balance strong import and export activities in order to achieve optimal levels of viral gene expression is incompletely understood. We provide evidence that multimerization provides a mechanism by which Rev transiently masks its NES peptide, thereby biasing its trafficking to and retention within the nucleus. Targeted pharmacological disruption of Rev-Rev interactions should perturb multiple Rev activities, both Rev-RNA binding and Rev's trafficking to the nucleus in the first place.

Nuclear export signal of IkappaBalpha interferes with the Rev-dependent posttranscriptional regulation of human immunodeficiency virus type I

1997 ◽  
Vol 110 (22) ◽  
pp. 2883-2893
Author(s):  
F. Bachelerie ◽  
M.S. Rodriguez ◽  
C. Dargemont ◽  
D. Rousset ◽  
D. Thomas ◽  
...  
Keyword(s):  
Dna Binding ◽  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Binding Activity ◽  
Nuclear Accumulation ◽  
Viral Rnas ◽  
Dna Binding Activity ◽  
Nf Kappab ◽  
Export Signal ◽  
Hiv 1

De novo synthesized IkappaBalpha accumulates transiently in the nucleus where it inhibits NF-kappaB-dependent transcription and reduces nuclear NF-kappaB content. A sequence present in the C-terminal domain of IkappaBalpha and homologous to the HIV-1 Rev nuclear export signal (NES) has been recently defined as a functional NES conferring on IkappaBalpha the ability to export IkappaBalpha/NF-kappaB complexes. Rev utilises its RNA-binding activity and NES sequence to promote specifically the transport of unspliced and monospliced viral RNAs to the cytoplasm. The object of this work was to determine if nuclear IkappaBalpha could interfere with Rev-dependent transport of viral RNA from the nucleus to the cytoplasm. We report that accumulation of IkappaBalpha in the cell nucleus blocks viral replication. This effect could be dissociated from the capacity of IkappaBalpha to inhibit NF-kappaB-DNA-binding activity and required a functional IkappaBalpha NES motif. Indeed, mutation of the NES abrogated the capacity of IkappaBalpha to inhibit Rev-dependent mechanisms involved in the replication of either wild-type or NF-kappaB-mutated HIV-1 molecular clones. Nuclear accumulation of a reporter protein tagged with a nuclear localization signal (NLS) and fused to the IkappaBalpha NES motif (NLS-PK-NES) was sufficient to inhibit HIV-1 replication at a post-transcriptional level by specifically blocking the expression of a Rev-dependent gene. Furthermore, in cells pulsed with TNF, a treatment which favors nuclear accumulation of newly synthesized IkappaBalpha, NLS-PK-NES expression promoted sustained accumulation of nuclear NF-kappaB lacking DNA-binding activity. This NES-mediated accumulation of inactive nuclear NF-kappaB is likely the consequence of interference in the IkappaBalpha-mediated export of NF-kappaB. These findings indicate that IkappaBalpha and Rev compete for the same nuclear export pathway and suggest that nuclear accumulation of IkappaBalpha, which would occur during normal physiological cell activation process, may interfere with the Rev-NES-mediated export pathway of viral RNAs, thus inhibiting HIV-1 replication.

HIV-1 rev nuclear export signal binding peptides isolated by phage display

1998 ◽  
Vol 283 (1) ◽  
pp. 245-254 ◽  
Author(s):  
Allan Jensen ◽  
Torben Heick Jensen ◽  
Jørgen Kjems
Keyword(s):  
Phage Display ◽  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Binding Peptides ◽  
Export Signal ◽  
Hiv 1

scholarly journals Amino Acid Exchanges in the Putative Nuclear Export Signal of Adenovirus Type 5 L4-100K Severely Reduce Viral Progeny due to Effects on Hexon Biogenesis

2012 ◽  
Vol 87 (3) ◽  
pp. 1893-1898 ◽  
Author(s):  
Orkide O. Koyuncu ◽  
Thomas Speiseder ◽  
Thomas Dobner ◽  
Melanie Schmid
Keyword(s):  
Amino Acid ◽  
Nuclear Export ◽  
Late Phase ◽  
Nuclear Export Signal ◽  
Virus Production ◽  
Adenovirus Type ◽  
Progeny Virus ◽  
Selective Translation ◽  
Adenovirus Type 5 ◽  
Export Signal

ABSTRACTThe adenovirus type 5 nonstructural L4-100K protein is indispensable for efficient lytic infection. During the late phase, L4-100K promotes selective translation of viral late transcripts and mediates the trimerization of the major capsid protein hexon. In the present study, the role of a potential nuclear export signal in L4-100K was investigated. Intriguingly, amino acid substitutions in this sequence resulted in severely diminished progeny virus production, seemingly by precluding proper hexon biogenesis.

scholarly journals A structured retroviral RNA element that mediates nucleocytoplasmic export of intron-containing RNA.

1997 ◽  
Vol 17 (1) ◽  
pp. 135-144 ◽  
Author(s):  
R K Ernst ◽  
M Bray ◽  
D Rekosh ◽  
M L Hammarskjöld
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Regulatory Proteins ◽  
Cellular Factors ◽  
Immunodeficiency Virus ◽  
Rna Export ◽  
Viral Regulatory Proteins ◽  
Responsive Element ◽  
Nucleocytoplasmic Export ◽  
Hiv 1

A common feature of gene expression in all retroviruses is that unspliced, intron-containing RNA is exported to the cytoplasm despite the fact that cellular RNAs which contain introns are usually restricted to the nucleus. In complex retroviruses, the export of intron-containing RNA is mediated by specific viral regulatory proteins (e.g., human immunodeficiency virus type 1 [HIV-1] Rev) that bind to elements in the viral RNA. However, simpler retroviruses do not encode such regulatory proteins. Here we show that the genome of the simpler retrovirus Mason-Pfizer monkey virus (MPMV) contains an element that serves as an autonomous nuclear export signal for intron-containing RNA. This element is essential for MPMV replication; however, its function can be complemented by HIV-1 Rev and the Rev-responsive element. The element can also facilitate the export of cellular intron-containing RNA. These results suggest that the MPMV element mimics cellular RNA transport signals and mediates RNA export through interaction with endogenous cellular factors.

scholarly journals The HIV-1 Rev Activation Domain is a nuclear export signal that accesses an export pathway used by specific cellular RNAs

Cell ◽  
1995 ◽  
Vol 82 (3) ◽  
pp. 475-483 ◽  
Author(s):  
Utz Fischer ◽  
Jochen Huber ◽  
Wilbert C Boelens ◽  
Lain W Mattajt ◽  
Reinhard Lührmann
Keyword(s):  
Nuclear Export ◽  
Nuclear Export Signal ◽  
Activation Domain ◽  
Export Pathway ◽  
Export Signal ◽  
Hiv 1
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